CPI assesses changes in the cost of living by measuring changes consumer pay for a set of items. CPI serves as the headline figure for inflation. Simply put, inflation reflects a decline in the purchasing power of the dollar, where each dollar buys fewer goods and services. In terms of measuring inflation, CPI is the most obvious way to quantify changes in purchasing power. The report tracks changes in the price of a basket of goods and services that a typical American household might purchase. An increase in the Consumer Price Index indicates that it takes more dollars to purchase the same set basket of basic consumer items.

Inflation is generally bad news for the economy, causing instability, uncertainty and hardship. To address inflation, the Fed may raise interest rates. However, the Fed relies on the PCE Deflator as its primary gauge of inflation because the CPI does not account for the ability of consumer to substitute out of CPI’s set. Price changes tend to cause consumers to switch from buying one good to a less expensive-other, a tendency that the fixed-basket CPI figure does not yet account for. Given that the PCE Deflator is a more comprehensive calculation, based on changes in consumption; it is the figure the Fed prefers.

The figure is released monthly, as either a month over month annualized percentage change, or percentage change for the full year. The figure is seasonally adjusted to account seasonal consumption patterns.

On A Technical Note: The CPI includes over 200 categories of goods and services included, divided into 8 main groups, each with a different weight: Housing, Transportation, Food, Medical Care, Education and Communication, Recreation, Apparel, and Other Goods and Services.

CPI Excluding Food and Energy – United States

The CPI is also reported excluding food and energy; two of its most volatile components. These components are particularly sensitive to temporary economic factors like oil prices, natural disasters and seasonal affects. Consequently, CPI excluding Food and Energy provides a more stable figure, but at the cost of overlooking two significant sectors in the economy (together food and energy comprise nearly a quarter of the goods included in the CPI).